The invention relates to a novel manufacturing process for compositions that can be used as emulsifying and dispersing surfactants. It also relates to the compositions obtained and their uses.
In U.S. Pat. No. 6,221,920, the Assignee described a process for the production of a composition consisting of a mixture containing at least amides, amines, ester-amides, ester-amines, salts of amines and mono-glycerides, deriving from the monomeric, dimeric, trimeric and/or tetrameric fatty acids contained in a polymerized polyunsaturated oil, this process comprising the transamdification (and transesterification) reaction of a thermally polymerized polyunsaturated oil, with at least one aminoalcohol, used in excess.
The composition obtained could be used, without any purification, as an emulsifying and dispersing surfactant, as such or after dilution with various solvents, such as, for example, aromatic fractions, various alcohols or also certain fatty acid esters.
It was indicated that the compositions thus defined could be used in a large number of applications, for example, as emulsifying agents allowing the formation of oil-in-water or water-in-oil emulsions, depending on the nature of the oil and the respective proportions of the two constituents (the hydrophilic constituent and the hydrophobic constituent). They could also be used as dispersing agents for solids or as foam stabilizers in a liquid or in an emulsion. A particular use which was indicated consisted of forming stable dispersions of ice in hydrocarbon media, for example, in light condensates of oil.
U.S. Pat. No. 5,958,844 describes another particular application of the compositions prepared according to the process of U.S. Pat. No. 6,221,920. This application consists of using them as dispersing additives for hydrates in suspension in fluids containing at least water, a gas and a liquid hydrocarbon (under conditions where hydrates may form the water and gas), in a manner so as to facilitate transport of same.
It has now been found in a surprising fashion that it is possible to improve the properties of these compositions by subjecting the polymerized oil, before reaction with the aminoalcohol, to an operation of entraining with water vapor having the effect of deodorizing the polymerized oil and eliminating degradation products which could be present in the polymerized oils and pose problems vis-a-vis certain media in which the final compositions may be used.
The invention therefore proposes a novel preparation process for compositions that can be used as emulsifying and dispersing surfactants defined by the fact that it comprises the following stages:
a) use (or preparation) of a polymerized oil by polymerization of a polyunsaturated vegetable or animal oil;
b) treatment of said polymerized oil by entrainment with water vapor; and
c) reaction of the polymerized oil thus treated with an excess of at least one aminoalcohol in the presence or not of a catalyst.
In order to prepare the compositions according to the invention, a commercial polymerized polyunsaturated oil can be used, such as the products known under the names xe2x80x9cstandoliexe2x80x9d, xe2x80x9cstand oilsxe2x80x9d or xe2x80x9cbodied oilsxe2x80x9d. In this case, stage (c) of the process is carried out directly.
In a different manner, if in stage (a) one has to prepare the polymerized oil, one can start from any vegetable or animal oil having a degree of polyunsaturation sufficient to allow the polymerization, by contact of the fatty chains containing diene or triene between themselves, as is the case, for example, for linoleic and linolenic acid. As examples the following oils can be mentioned: linseed, sunflower, safflower, china wood, grapeseed, soybean or corn, or certain fish oils, as well as any other oils having high levels of linoleic and/or linolenic acid. Linseed oil is preferred in the process according to the invention
An approximate composition in fatty acids of linseed oil is as follows:
palmitic acid: 5.5% by weight
stearic acid: 3.5% by weight
oleic acid: 19.0% by weight
linoleic acid: 14.4% by weight
linolenic acid: 57.6% by weight
The polymerization of a polyunsaturated oil can be carried out according to any appropriate method, thermally or by catalytic route. The polymerization by essentially thermal route can be carried out by simple heating to approximately 300xc2x0 C. under nitrogen. The heating time then determines a viscosity gradient of the polymerized oil, which can reach, after a heating time for example of 20 hours or more, a dynamic viscosity of 65 Pa.s at 20xc2x0 C.
The polymerization can also be carried out at 280-290xc2x0 C. under reduced pressure in the presence of anthraquinone or benzoquinone (see Nisshin Oils Mills, Yokohama, Japan, Nagakura and Coll. (1975), 48(4), 217-22).
When the polymerized polyunsaturated oil used in the manufacturing process according to the invention is prepared, in order to reduce the duration of the polymerization and therefore the risk of forming undesirable degradation products, provision can also be made to catalyze the polymerization of the starting polyunsaturated oil by metals, such as for example, zinc, lead, tin or copper in the form of nitrates, chlorides or stearates, or also manganese in the form of oxide or of a salt. In this respect, there can be mentioned for example the heating for 6 hours of the linseed oil with copper (II) nitrate in a proportion of 0.5 to 2% by weight relative to the starting oil described by Sil S. and Koley S. N., Department of Chemical Technology, Univ. of Calcutta (1987) 37(8), 15-22.
Among the metal catalysts used to reduce the duration of the reaction, a salt or dioxide of manganese MnO2 can be advantageously used, for example in a proportion of 0.5 to 2% by weight relative to the starting oil. Such catalysts can in fact be left in the final product without causing problems of toxicity or compatibility with the media in which the additive will be finally used.
In all cases, in order to be able to be used in the production process according to the invention, the polymerized oils advantageously have a dynamic viscosity at 20xc2x0 C. of 5 to 65 Pa.s and preferably of 10 to 20 Pa.s. They generally have an acid number of 8 to 20. Similar viscosities are generally preserved after the treatment by entraining with water vapor of stage (b), as will be described below. As regards the acid number, it is generally lowered by this treatment.
The composition of the oligomers of fatty acids contained in a polymerized linseed oil having a dynamic viscosity at 20xc2x0 C. of 65 Pa.s is given hereafter, by way of example:
monomeric fatty acids: 44.10% by weight
dimeric fatty acids: 32.30% by weight
trimeric fatty acids: 14.50% by weight
higher oligomers 9.10% by weight.
These values were obtained after methanolysis of the polymerized oil, and the separation of the methyl esters of the different fatty acids (monomers, dimers, trimers and higher oligomers) was achieved by gel-permeation chromatography (GPC). The acid number of the polymerized oil is equal to 16 mg of KOH/g.
The product of the polymerization reaction, after methanolysis, can be purified by distillation in order to eliminate from it the esters fraction corresponding to the monomeric fatty acids. A mixture is then obtained which contains approximately 1% of monomeric acids, approximately 75% of dimeric acids, approximately 19% of trimeric acids and approximately 5% of higher oligomers.
In stage (b) of the process according to the invention, the polymerized oil which is used or as obtained at the end of stage (a) is subjected to an entrainment with water vapor.
In order to carry out this treatment, a stream of dry water vapor is passed over the polymerized oil to be treated, in a quantity of 5 to 30% by weight relative to the oil for example, at a temperature of 180 to 250xc2x0 C., under a vacuum of 7 to 2.5 kPa and for a period of 1 to 5 hours.
The amidification reaction of the fatty acids by the primary or secondary functions of the aminoalcohols used in stage (c) of the process according to the invention, accompanied by the transesterification of the ester functions of glycerol by the alcohol functions of said aminoalcohols is known from the prior art and can be carried out at a temperature of 100 to 200xc2x0 C. and preferably 110 to 160xc2x0 C., preferably without catalyst with elimination of the water vapor as it forms, either by using a third solvent in order to obtain an azeotrope, or by operating without solvent, but by elimination of the water by distillation under reduced pressure (see for example U.S. Pat. No. 2,089,212 and the article by Harry Kroll and Herbert Nadeau in J.A.O.C.S. 34, 323-326, June 1957). The reaction can also be catalyzed, which appreciably reduces its duration. As catalysts, alkaline alcoholates of lithium, sodium or potassium methylate or ethylate type are generally used. The reaction time is then 15 to 200 minutes; preferably, the reaction is stopped after 100 minutes.
The molar ratio of the aminoalcohol to the polymerized oil, expressed as the moles of fatty acids which it contains, is generally from 1/1 to 2/1, preferably, of the order of 1.5/1.
The aminoalcohols which are capable of being used are, for example, monoethanolamine, monopropanolamine, monoisopropanolamine, 1-amino-butanol, 2-amino-1-butanol, N-methylethanolamine, N-butylethanolamine, pentanolamine, hexanolamine, cyclohexanolamine, polyalcoholamines or also polyalkoxyglycolamines, as well as aminated polyols such as diethanolamine, diisopropanolamine or trihydroxy-methylaminomethane. Diethanolamine will preferably be used.
The product obtained by the process according to the invention consists of a composition mainly containing compounds with ester and amide functions, in particular in the form of ester-amides, as well compounds with amine functions, such as ester-amines, the salts of amines, monoglycerides and diglycerides, formed from monomeric, dimeric, trimeric and/or tetrameric fatty acids, contained in the polymerized polyunsaturated oil. It can be used directly without any purification, either as such or after dilution in a solvent suitable for the emulsifying application chosen. The compatible solvents which may be used can be chosen from the aromatic solvents, such as for example toluene or xylenes, the fractions of aromatic solvents; monoalcohols, such as for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol or dodecanol; diols such as for example monopropylene glycol or diethylene glycol; and all the esters of C1 to C4 monoalcohols and the C6 to C22 fatty acids, such as for example those deriving from vegetable or animal oils or fats, as well as the same pure esters, such as for example methyl or ethyl hexanoate or octoate.
The esters of the C1 to C4 monoalcohols and the C6 to C22 fatty acids deriving from vegetable or animal oils or fats can be chosen for example from the methyl and ethyl esters of the following oils: copra, babassu, palm nut, tucum, murumuru, palm, shea butter, olive, peanut, kapok, bitter date, papaya, colocynth, croton, earth almond, spurge, hemp seed, beech, okra, curcas, cameline, safflower, Niger seed, sunflower, oleic sunflower, rubber tree, coconut, jalop, walnut, corn, soybean, cotton seed, sorghum, grapeseed, linseed, tobacco, common wood turpentine, afzellie, swede, wild mustard seed, brown mustard seed, china wood, candlenut, tung tree, amoora, fir, cramble, perilla, erucic rapeseed, low eruric rapeseed, oleic rapeseed, sesame, cocoa butter, tall oil, wheatgerm and castor, as well as certain fish oils; and among the methyl and ethyl esters of fats such as lard, tallow and melted butter, as they are or partially hydrogenated.
In certain applications where it can have contact with the environment, the use of aromatic solvents must be avoided and solvents having a non-toxicity and a certain biodegradability must be used instead; in this case, fatty esters originating from vegetable bases will advantageously be used as solvents, such as for example the methyl or ethyl ester of rapeseed oil.
The compositions obtained by the process according to the invention are of particular use as dispersing additives for hydrates in oil effluents intended to reduce the tendency to agglomerate of said hydrates. In this use, these compositions are added to the fluid to be treated at concentrations ranging in general from 0.1 to 5% by weight, preferably 0.2 to 2% by weight relative to the water.
The entire disclosure of all applications, patents and publications, cited above and below, and of corresponding French application 99/06448, filed May 19, 1999 are hereby incorporated by reference.
The following examples illustrate the invention but must in no way be considered as limitative. Example 3 is given by way of comparison.